VirtualBox + Powershell = genius (?) in the box

Today I'm facing another strange behavior of the command-line interface "vboxmanage.exe" for Oracle's VirtualBox.

Here is the Powershell code I'm executing on a remote machine to reboot a virtual machine:

$VM = "WindowsXP";

Invoke-Command -ScriptBlock {vboxmanage controlvm $args reset} -ArgumentList $VM ComputerName 10.3.2.127

Ok, I got an error that is:

VBoxManage.exe: error: Invalid machine state: PoweredOff

+ CategoryInfo : NotSpecified: (VBoxManage.exe:...ate: PoweredOff:String) [], RemoteException

+ FullyQualifiedErrorId : NativeCommandError

VBoxManage.exe: error: Details: code VBOX_E_INVALID_VM_STATE (0x80bb0002), component Console, interface IConsole, callee IUnknown

Context: "Reset()" at line 124 of file VBoxManageControlVM.cpp

The weird thing is that on the machine that hosts the VM (10.3.2.127) the reset works fine.

I checked the execution state on both the host and the remote machine and... guess what... I discovered that the state was different: Powered Off on the remote machine, and running on the host.

host: State: running (since 2011-10-22T22:20:35.359000000)

remote: State: powered off (since 2011-10-18T14:39:32.000000000)

To be sure it was the same machine, I checked the UUID of the machine, and it is the same.

And the machine is accessible, too (it works!)

Another strange thing is the time since the VM results stopped on the remote machine, actually 4 days before, probably since the last try in "reset" the VM.

And here is the deal. When then I tried to start the machine remotely, I got this error:

Invoke-Command -ScriptBlock {vboxmanage startvm "WindowsXP" --type headless} -ArgumentList "WindowsXP" -ComputerName 10.3.2.127

Waiting for VM "WindowsXP" to power on...

VBoxManage.exe: error: Failed to open release log (could not open file 'C:\Documents and Settings\perfmon\VirtualBox VMs\WindowsXP\Logs\VBox.log' (fOpen=0x322), VERR_SHARING_VIOLATION)

+ CategoryInfo : NotSpecified: (VBoxManage.exe:...RING_VIOLATION):String) [], RemoteException

+ FullyQualifiedErrorId : NativeCommandError

VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component Console, interface IConsole, callee

Then I recalled that the last time I started the VM directly from the host, and not from the remote machine.

Like this, the handler of the log file is still associated to the process which started the machine (on the host), and the powershell process, which tries to access the machine, cannot get the handler. This results in a false information about the state of the machine.

Thus, to solve the problem, I powered off the VM on the host, and I started it successfully on the remote machine:

Invoke-Command -ScriptBlock {vboxmanage startvm "WindowsXP" --type headless} -ArgumentList "WindowsXP" -ComputerName 10.3.2.127

Waiting for VM "WindowsXP" to power on...

VM "WindowsXP" has been successfully started.

and then I checked if the reset was working:

Invoke-Command -ScriptBlock {vboxmanage controlvm $args reset} -ArgumentList "WindowsXP" -ComputerName 10.3.2.127

and the machine state was:

State: running (since 2011-10-28T12:54:58.718000000)

Here we go!!! :)

Ivano 1, VirtualBox 0

Microsoft SQL (and other programs) crash due to mscorwks.dll

This kind of crash seems to be provoked in systems where several versions of .NET Framework are installed. About my case, I had .Net Framework 2.0 SP1 and .Net Compact Framework 2.0 SP2 (and also 3.0 and 3.5).

Just uninstalling .Net Compact Framework 2.0 SP2 solved the problem :)

In another case that I had, it was way harder, as I was not able to uninstall or reinstall any of the .Net frameworks. Luckily I found here the solution to my problem (http://blogs.msdn.com/b/astebner/archive/2009/02/18/9432938.aspx). It seems there is a tool coming with the framework that allows to you to repair any damaged file/registry key related to the framework.

Ciao!

Erase the duplicates in a DB table (and "copy" tables!)

What if your table has got some duplicates (because you DO NOT define PRIMARY KEYS...)???

Well, we can select distinct rows from the table, and then create a new table with the resultset.
The syntax that we need is the following:

SELECT DISTINCT * INTO [new_table] FROM [old_table]

In addition, if the table already exist, we can use the INSERT INTO command:

INSERT INTO [new_table]
SELECT * FROM [old_table]

That's all!!! :)

when trying to use psexec.exe on a remote machine, it may happen that the following error may occurr:

Logon failure: unknown user name or bad password.

To solve this problem, just change the value in Local Security Policy -> Security options, change:

• Network access: Sharing and security model for local account (Classic)

...and that's all!!! :)

Connect from (Matlab on) MACOSX to Microsoft SQL Server (2005 Express)???

OK, that's a bit malad.
We have two ways: ODBC (proprietary, I downloaded OpenLink ODBC Adminstrator, with 30days trial), easily configurable, or JDBC (needed if you're using, for instance, Matlab for MacOS/Linux).
About JDBC, this link (http://www.razorsql.com/articles/sql_server_mac.html) says that we can have the JDBC driver in two ways:

The easiest way to connect to MS SQL Server from Mac is with a JDBC (Java Database Connectivity) driver. Since Mac OS X comes with Java pre-installed, the only thing that needs to be downloaded is a suitable JDBC driver. There are two options for JDBC driver. Once is the open source jTDS driver. The other is the JDBC driver from Microsoft.

About the JDBC driver from Microsoft, I'm not able to understand how to install it... and to use it...
About the iTDS driver, I downloaded it, but it comes like the Microsoft driver: basically a .jar file.

What to do?

I found it! ;)
JDBC is not like ODBC connection. ODBC is Microsoft-proprietary, and need some "tool" (like the one from OpenLink) to interact with the OS. JDBC, on the contrary, needs only an application to call the jar file, and so the libraries in it.

My problem was to connect to a Microsoft SQL Server 2005 with Matlab for MacOSX.
Matlab come with the Database Toolbox, and reading the help (...carefully reading...), I learned something. Matlab can use ODBC on Windows systems, and ODBC/JDBC on other systems. So, as we are in MacOSX, we are going to use a JDBC, previously downloaded (done!).
Now, guess wath? As Matlab is an application, and it's developed in Java too (and comes with his Java VM!!!), it's only necessary to understand where to indicate to Matlab the path of the JDBC jar-file.

I found this:

Specify the location of the drivers file in the MATLAB Sun Java classpath by adding this file's path to the matlabroot/toolbox/local/classpath.txt file.

I found it in /Applications/MATLAB_R2009b.app/toolbox/local/ , and I add the path "/Users/ivanoirrera/lib/MSSQL_JDBC/sqljdbc.jar" (in my case, but you can put the jar-library everywhere you want). Then restart Matlab.
After it, run "querybuilder", and click Query > Define JDBC Data Source.

Now, specify correctly the information the connection needs.
In my case:

name = master
driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver"
URL = //10.3.1.200:1433/master

Note: the Java version used by Matlab is 1.6, and Microsoft JDBC drivers 2.0 do not support this version! To solve the problem, download the "Microsoft SQL Server 2005 JDBC Driver 1.2" version.

Anyway... now it shows no problem... but it blocks :(

(to be completed)

Cannot start the Perfmon service

The Perfmon service (with 387 variables) cannot start, due to this problem:

Event Type: Error
Event Source: PDH
Event Category: None
Event ID: 3041
Date: 25-12-2010
Time: 20:43:29
User: N/A
Computer: TARGETREAL
Description:
The description for Event ID ( 3041 ) in Source ( PDH ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for user ''. The user is not associated with a trusted SQL Server connection..
Data:
0000: 14 .

To solve this problem, modify the registry on Controller (and Target?) systems.
Open Control Panel -> Administration tools -> Local Security Policy -> User Righ Assignment, and change the voices:

• Access computer from the net (Everyone)
• Deny access to this computer (erase Guest, if exists)
• Enable computer and user accounts to access... (Everyone)
• Enable computers and user to be trusted for delegation (Everyone, Guest, ...)
  

Moreover, in Local Security Policy -> Security options, change:

• Network access: Sharing and security model for local account (Classic)

Then, you may have this problem:

Event Type: Error
Event Source: PDH
Event Category: None
Event ID: 3041
Date: 22-02-2011
Time: 21:04:59
User: N/A
Computer: TARGETREAL
Description:
The description for Event ID ( 3041 ) in Source ( PDH ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for user 'LAB\Guest'..
Data:
0000: 18 .

To solve this problem, you must add the user GUEST in SQL Server (under the folder Security -> Logins).
Give to him the sysadmin right, or less.

Install Windows XP on a Asus P5S800-VM motherboard

It's only necessary to enter the Bios, and in the first table change the "SATA" setting to "Normal".
Then the motherboard will emulate the SATA disk as PATA.
That's all :)